Put everything except the milk in a food processor and blitz until the mixture resembles coarse crumbs. Tip into a bowl, then add just enough milk to bring it together into a firm dough. This uncooked dough will keep in the fridge for several days (as long as the milk in it remains fresh).

This makes a very firm, solid dough and, if it's been in the fridge, it will be rock hard, so let it come to room temperature before rolling. Preheat the oven to 160C/325F/gas mark 3 and lightly grease two baking sheets. Put the dough between two sheets of clingfilm or baking parchment, and roll out until 2-3mm thick. Work quickly because it can become sticky as it warms up (return it to the fridge for a bit if this happens). Use a plain round cookie cutter to stamp out the biscuits. Arrange on the baking sheets and bake for 10-12 minutes, until pale golden and just beginning to turn brown around the edges. Leave to cool, then store in an airtight container.